Many applications of thermoplastic materials require a low gloss surface, including for example, thermoplastic panels with a wood-like appearance. Current approaches used to lower plastic surface gloss include the use of 5 to 15 wt % of 1 to 10 micron sized inorganic fillers and/or crosslinked polymeric particles plastic additives based on the total weight of the plastic formulation (i.e., base plastic or polymer plus all additives). Such inorganic and polymeric particles generally lower surface gloss by extending from the plastic surface providing a rough surface which destructively scatters light thereby decreasing gloss. Such additives, however, tend to significantly reduce the impact resistance of the plastic to which they are added. In addition, such additives generally make the final plastic formulation opaque.
Another issue with such known additives is the inability to maintain low gloss. Specifically, such particulate additives tend to be covered by the plastic material upon exposure to heat as the matrix polymer tends to flow around and over the particulate additives when heated after initial processing. For example, during thermal forming (or thermoforming), gloss will increase significantly for plastics with particulate additives. The particulate additive approach to decreasing the gloss of plastic surfaces is further subject to burnishing. Burnish resistance is the term used to describe resistance to gloss increase by rubbing. That is, the portion of the particulates which extend out from the plastic surface may be removed or broken off with rubbing of the plastic surface thereby leading to a smoother surface and increased gloss. A plastic formulation with low surface gloss, good impact resistance, good burnish resistance and which may be heat treated post initial processing without a substantial increase in gloss would be very desirable. Moreover, it would be desirable to have a plastic formulation in which the gloss reduction additive is compatible with the thermoplastic polymer matrix so as to provide a uniform sheet in melt processing, and specifically which is compatible with polymethyl methacrylate (“PMMA”), acrylonitrile butadiene styrene polymer (“ABS”), poly(styrene-co-acrylonitrile) (“SAN”), polyvinylchloride (“PVC”), acrylonitrile/styrene acrylate (“ASA”), chlorinated polyvinylchloride (“CPVC”), polylactic acid (“PLA”), polycarbonate (“PC”), polyesters, such as poly(ethylene terephthalate) (“PET”), poly(butylene terephthalate) (“PBT”), and polyethylene terephthalate glycol (“PETG”).